I'm trying to figure out the forces on this arm crane when alpha angle is changed from 0 degrees, 30 degrees, 45 degrees, 60 degrees and 90 degrees. What I'm confused about is how to input the angle in maple. Do I add 45 degrees and alpha angle together?

Apparently the load (L) is not unknown but I'm not sure how its not unknown when I am not given any number for it. How do you find out the load (L)?!

Here's the picture:
http://postimage.org/image/x4s13q3b7/